Correct Answer: B

Rationale: The word 'whom' should be used instead of 'who' in the sentence to make it grammatically correct. 'Who' is used as the subject of a sentence, while 'whom' is used as the object. Therefore, the correct form of the sentence should be: 'For whom was that email intended?' Choices A, C, and D are used correctly in the sentence and do not need any changes.

Correct Answer: B

Rationale: The word 'stationary' in the sentence should be spelled as 'stationary.' 'Stationery' refers to writing paper and other office supplies, while 'stationary' means not moving or still. In this context, the correct word should be 'stationary' to describe the chairs that are not moving.

Correct Answer: B

Rationale: The word 'quickly' is used incorrectly in the sentence. The correct word that should be used here is 'speedily.' 'Quickly' is an adverb that describes the speed at which an action is performed. However, in this context, the sentence needs an adverb that conveys doing something in a hurried or rushed manner, which is 'speedily.' Therefore, the sentence should read as: 'If you calculate too speedily, you may possibly fail to get the right answer.' The other choices ('calculate,' 'possibly,' 'right') are used appropriately in the sentence and do not need to be changed.

Correct Answer: A

Rationale: The correct sentence is 'Because she was uncertain of her abilities, Renee asked for help.' This sentence uses a comma after the introductory phrase 'Because she was uncertain of her abilities' to set it off from the main clause 'Renee asked for help.' The comma helps to separate the two parts of the sentence clearly and indicates the pause that should be there when reading it aloud. Options B, C, and D are incorrect because they either use a semicolon incorrectly or have commas placed incorrectly within the sentence.

Correct Answer: D

Rationale: The word 'their' is the best substitute for the underlined words in the sentence because it refers to Stu's roommates in a possessive form, indicating that the housekeeping belongs to them. 'His' (Choice A) refers to Stu, not the roommates. 'Hers' (Choice B) is incorrect as it refers to a female possessive form. 'Them' (Choice C) is a pronoun for a group of people but does not show possession, making it unsuitable in this context.